Collagen tube lined with genetically modified Schwann cells with increased motility: A new promising bioartificial nerve graft

Background: In the present study we designed a new artificial nerve graft consisting of a type I collagen tube lined with sialyl-transferase-X-transduced Schwann cells (SC), with increased motility, and investigated its efficacy in bridging nerve gaps in the rat sciatic nerve model. Methods: One hundred and twenty male Wistar rats were randomized in 4 groups of 30. A defect, 12 mm long in the left sciatic nerve, was created and repaired in an end-to-end fashion with a nerve autograft (group A), collagen tube (group B), collagen tube lined with SC (group C), and collagen tube lined with Sialyl-Transferase-X-transduced SC (group D). Walking track analysis, electrophysiological and histological-morphometric studies were carried out 4, 6, 8, 10, and 12 weeks postoperatively. Results: Data analysis showed that muscle action potential in group D was significantly higher than in groups B and C in the course of time (P < 0.05 by ANOVA) and higher but not statistically significant than in group A. Walking track analysis verified these findings since the toe spread ratio was very similar between groups A and D (P > 0.1 by ANOVA) and significantly higher than in groups B and C (P < 0.05 by ANOVA). Light microscopy showed that the appearance of the regenerated nerves was more mature in group D than in both groups B and C and comparable to group A, throughout the observation period. Morphometric evaluation demonstrated that although the number of regenerated fibers did not differ significantly among the experimental groups, the presence of genetically modified SC in group D promoted fiber maturation as indicated by significantly greater fiber diameter and myelin thickness compared to all other groups (P < 0.001 by ANOVA), throughout the observation period. Conclusions: These results highlight the role of the Schwann cells' increased motility in peripheral nerve regeneration and suggest that this artificial nerve graft may be a useful alternative to the present gold standard of conventional nerve grafts for bridging nerve defects.